Temporary main switch arrangement for connecting power supplies of a power tool and an elevator

A temporary main switch arrangement of an elevator includes a first switch in the electricity supply circuit of the power tool and a second switch in the electricity supply circuit of the elevator. The first switch may be fitted into the electricity supply circuit of the power tool and the second switch may be fitted into the electricity supply circuit of the elevator. When modernizing an elevator, the temporary main switch arrangement is fitted into the building's electrical system between the building's distribution circuit, the electricity supply circuit of the power tool and the electricity supply circuit of the elevator; the first switch disconnects the electricity supplies from the electricity supply circuit of the elevator; the second switch connects the electricity supplies to the electricity supply circuit of the power tool; and modernization of at least the electricity supply circuit of the elevator is performed.